Godzilla vs. MechaGodzilla (1974) Plot Synopsis:

An Okinawan priestess claims a monster will rise to attack Japan. Soon enough Godzilla lays waste to Tokyo and nearly kills Anguirus. The imposter is revealed when the real Godzilla arrives; aliens from the third planet of the blackhole have created a MechaGodzilla to match Godzilla's strength! With Godzilla presumed dead, and MechaGodzilla badly damaged, the Black Hole Aliens set their sights on a potential threat-- The Okinawan legend of King Ceasar. Interpol races the aliens for the key to King Ceasar's revival. Meanwhile, MechaGodzilla is repaired for battle.